1%% Licensed under the Apache License, Version 2.0 (the "License"); 2%% you may not use this file except in compliance with the License. 3%% You may obtain a copy of the License at 4%% 5%% http://www.apache.org/licenses/LICENSE-2.0 6%% 7%% Unless required by applicable law or agreed to in writing, software 8%% distributed under the License is distributed on an "AS IS" BASIS, 9%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 10%% See the License for the specific language governing permissions and 11%% limitations under the License. 12%% 13%% @copyright 1999-2002 Richard Carlsson. 14%% @author Richard Carlsson <carlsson.richard@gmail.com> 15%% @doc Basic functions on Core Erlang abstract syntax trees. 16%% 17%% <p>Syntax trees are defined in the module <a 18%% href="cerl"><code>cerl</code></a>.</p> 19%% 20%% @type cerl() = cerl:cerl() 21 22-module(cerl_trees). 23 24-export([depth/1, fold/3, free_variables/1, get_label/1, label/1, label/2, 25 map/2, mapfold/3, mapfold/4, next_free_variable_name/1, 26 size/1, variables/1]). 27 28-import(cerl, [alias_pat/1, alias_var/1, ann_c_alias/3, ann_c_apply/3, 29 ann_c_binary/2, ann_c_bitstr/6, ann_c_call/4, 30 ann_c_case/3, ann_c_catch/2, ann_c_clause/4, 31 ann_c_cons_skel/3, ann_c_fun/3, ann_c_let/4, 32 ann_c_letrec/3, ann_c_module/5, ann_c_primop/3, 33 ann_c_receive/4, ann_c_seq/3, ann_c_try/6, 34 ann_c_tuple_skel/2, ann_c_values/2, apply_args/1, 35 apply_op/1, binary_segments/1, bitstr_val/1, 36 bitstr_size/1, bitstr_unit/1, bitstr_type/1, 37 bitstr_flags/1, call_args/1, call_module/1, call_name/1, 38 case_arg/1, case_clauses/1, catch_body/1, clause_body/1, 39 clause_guard/1, clause_pats/1, clause_vars/1, concrete/1, 40 cons_hd/1, cons_tl/1, fun_body/1, fun_vars/1, get_ann/1, 41 let_arg/1, let_body/1, let_vars/1, letrec_body/1, 42 letrec_defs/1, letrec_vars/1, module_attrs/1, 43 module_defs/1, module_exports/1, module_name/1, 44 module_vars/1, primop_args/1, primop_name/1, 45 receive_action/1, receive_clauses/1, receive_timeout/1, 46 seq_arg/1, seq_body/1, set_ann/2, subtrees/1, try_arg/1, 47 try_body/1, try_vars/1, try_evars/1, try_handler/1, 48 tuple_es/1, type/1, update_c_alias/3, update_c_apply/3, 49 update_c_binary/2, update_c_bitstr/6, update_c_call/4, 50 update_c_case/3, update_c_catch/2, update_c_clause/4, 51 update_c_cons/3, update_c_cons_skel/3, update_c_fun/3, 52 update_c_let/4, update_c_letrec/3, update_c_module/5, 53 update_c_primop/3, update_c_receive/4, update_c_seq/3, 54 update_c_try/6, update_c_tuple/2, update_c_tuple_skel/2, 55 update_c_values/2, values_es/1, var_name/1, 56 57 map_arg/1, map_es/1, 58 ann_c_map/3, 59 update_c_map/3, 60 is_c_map_pattern/1, ann_c_map_pattern/2, 61 map_pair_key/1,map_pair_val/1,map_pair_op/1, 62 ann_c_map_pair/4, 63 update_c_map_pair/4 64 ]). 65 66 67%% --------------------------------------------------------------------- 68 69%% @spec depth(Tree::cerl()) -> integer() 70%% 71%% @doc Returns the length of the longest path in the tree. A leaf 72%% node has depth zero, the tree representing "<code>{foo, 73%% bar}</code>" has depth one, etc. 74 75-spec depth(cerl:cerl()) -> non_neg_integer(). 76 77depth(T) -> 78 case subtrees(T) of 79 [] -> 80 0; 81 Gs -> 82 1 + lists:foldl(fun (G, A) -> erlang:max(depth_1(G), A) end, 0, Gs) 83 end. 84 85depth_1(Ts) -> 86 lists:foldl(fun (T, A) -> erlang:max(depth(T), A) end, 0, Ts). 87 88 89 90%% @spec size(Tree::cerl()) -> integer() 91%% 92%% @doc Returns the number of nodes in <code>Tree</code>. 93 94-spec size(cerl:cerl()) -> non_neg_integer(). 95 96size(T) -> 97 fold(fun (_, S) -> S + 1 end, 0, T). 98 99 100%% --------------------------------------------------------------------- 101 102%% @spec map(Function, Tree::cerl()) -> cerl() 103%% 104%% Function = (cerl()) -> cerl() 105%% 106%% @doc Maps a function onto the nodes of a tree. This replaces each 107%% node in the tree by the result of applying the given function on 108%% the original node, bottom-up. 109%% 110%% @see mapfold/3 111 112-spec map(fun((cerl:cerl()) -> cerl:cerl()), cerl:cerl()) -> cerl:cerl(). 113 114map(F, T) -> 115 F(map_1(F, T)). 116 117map_1(F, T) -> 118 case type(T) of 119 literal -> 120 case concrete(T) of 121 [_ | _] -> 122 update_c_cons(T, map(F, cons_hd(T)), 123 map(F, cons_tl(T))); 124 V when tuple_size(V) > 0 -> 125 update_c_tuple(T, map_list(F, tuple_es(T))); 126 _ -> 127 T 128 end; 129 var -> 130 T; 131 values -> 132 update_c_values(T, map_list(F, values_es(T))); 133 cons -> 134 update_c_cons_skel(T, map(F, cons_hd(T)), 135 map(F, cons_tl(T))); 136 tuple -> 137 update_c_tuple_skel(T, map_list(F, tuple_es(T))); 138 map -> 139 update_c_map(T, map(F, map_arg(T)), map_list(F, map_es(T))); 140 map_pair -> 141 update_c_map_pair(T, map(F, map_pair_op(T)), 142 map(F, map_pair_key(T)), 143 map(F, map_pair_val(T))); 144 'let' -> 145 update_c_let(T, map_list(F, let_vars(T)), 146 map(F, let_arg(T)), 147 map(F, let_body(T))); 148 seq -> 149 update_c_seq(T, map(F, seq_arg(T)), 150 map(F, seq_body(T))); 151 apply -> 152 update_c_apply(T, map(F, apply_op(T)), 153 map_list(F, apply_args(T))); 154 call -> 155 update_c_call(T, map(F, call_module(T)), 156 map(F, call_name(T)), 157 map_list(F, call_args(T))); 158 primop -> 159 update_c_primop(T, map(F, primop_name(T)), 160 map_list(F, primop_args(T))); 161 'case' -> 162 update_c_case(T, map(F, case_arg(T)), 163 map_list(F, case_clauses(T))); 164 clause -> 165 update_c_clause(T, map_list(F, clause_pats(T)), 166 map(F, clause_guard(T)), 167 map(F, clause_body(T))); 168 alias -> 169 update_c_alias(T, map(F, alias_var(T)), 170 map(F, alias_pat(T))); 171 'fun' -> 172 update_c_fun(T, map_list(F, fun_vars(T)), 173 map(F, fun_body(T))); 174 'receive' -> 175 update_c_receive(T, map_list(F, receive_clauses(T)), 176 map(F, receive_timeout(T)), 177 map(F, receive_action(T))); 178 'try' -> 179 update_c_try(T, map(F, try_arg(T)), 180 map_list(F, try_vars(T)), 181 map(F, try_body(T)), 182 map_list(F, try_evars(T)), 183 map(F, try_handler(T))); 184 'catch' -> 185 update_c_catch(T, map(F, catch_body(T))); 186 binary -> 187 update_c_binary(T, map_list(F, binary_segments(T))); 188 bitstr -> 189 update_c_bitstr(T, map(F, bitstr_val(T)), 190 map(F, bitstr_size(T)), 191 map(F, bitstr_unit(T)), 192 map(F, bitstr_type(T)), 193 map(F, bitstr_flags(T))); 194 letrec -> 195 update_c_letrec(T, map_pairs(F, letrec_defs(T)), 196 map(F, letrec_body(T))); 197 module -> 198 update_c_module(T, map(F, module_name(T)), 199 map_list(F, module_exports(T)), 200 map_pairs(F, module_attrs(T)), 201 map_pairs(F, module_defs(T))) 202 end. 203 204map_list(F, [T | Ts]) -> 205 [map(F, T) | map_list(F, Ts)]; 206map_list(_, []) -> 207 []. 208 209map_pairs(F, [{T1, T2} | Ps]) -> 210 [{map(F, T1), map(F, T2)} | map_pairs(F, Ps)]; 211map_pairs(_, []) -> 212 []. 213 214 215%% @spec fold(Function, Unit::term(), Tree::cerl()) -> term() 216%% 217%% Function = (cerl(), term()) -> term() 218%% 219%% @doc Does a fold operation over the nodes of the tree. The result 220%% is the value of <code>Function(X1, Function(X2, ... Function(Xn, 221%% Unit) ... ))</code>, where <code>X1, ..., Xn</code> are the nodes 222%% of <code>Tree</code> in a post-order traversal. 223%% 224%% @see mapfold/3 225 226-spec fold(fun((cerl:cerl(), term()) -> term()), term(), cerl:cerl()) -> term(). 227 228fold(F, S, T) -> 229 F(T, fold_1(F, S, T)). 230 231fold_1(F, S, T) -> 232 case type(T) of 233 literal -> 234 case concrete(T) of 235 [_ | _] -> 236 fold(F, fold(F, S, cons_hd(T)), cons_tl(T)); 237 V when tuple_size(V) > 0 -> 238 fold_list(F, S, tuple_es(T)); 239 _ -> 240 S 241 end; 242 var -> 243 S; 244 values -> 245 fold_list(F, S, values_es(T)); 246 cons -> 247 fold(F, fold(F, S, cons_hd(T)), cons_tl(T)); 248 tuple -> 249 fold_list(F, S, tuple_es(T)); 250 map -> 251 fold_list(F, S, map_es(T)); 252 map_pair -> 253 fold(F, 254 fold(F, 255 fold(F, S, map_pair_op(T)), 256 map_pair_key(T)), 257 map_pair_val(T)); 258 'let' -> 259 fold(F, fold(F, fold_list(F, S, let_vars(T)), 260 let_arg(T)), 261 let_body(T)); 262 seq -> 263 fold(F, fold(F, S, seq_arg(T)), seq_body(T)); 264 apply -> 265 fold_list(F, fold(F, S, apply_op(T)), apply_args(T)); 266 call -> 267 fold_list(F, fold(F, fold(F, S, call_module(T)), 268 call_name(T)), 269 call_args(T)); 270 primop -> 271 fold_list(F, fold(F, S, primop_name(T)), primop_args(T)); 272 'case' -> 273 fold_list(F, fold(F, S, case_arg(T)), case_clauses(T)); 274 clause -> 275 fold(F, fold(F, fold_list(F, S, clause_pats(T)), 276 clause_guard(T)), 277 clause_body(T)); 278 alias -> 279 fold(F, fold(F, S, alias_var(T)), alias_pat(T)); 280 'fun' -> 281 fold(F, fold_list(F, S, fun_vars(T)), fun_body(T)); 282 'receive' -> 283 fold(F, fold(F, fold_list(F, S, receive_clauses(T)), 284 receive_timeout(T)), 285 receive_action(T)); 286 'try' -> 287 fold(F, fold_list(F, fold(F, fold_list(F, fold(F, S, try_arg(T)), 288 try_vars(T)), 289 try_body(T)), 290 try_evars(T)), 291 try_handler(T)); 292 'catch' -> 293 fold(F, S, catch_body(T)); 294 binary -> 295 fold_list(F, S, binary_segments(T)); 296 bitstr -> 297 fold(F, 298 fold(F, 299 fold(F, 300 fold(F, 301 fold(F, S, bitstr_val(T)), 302 bitstr_size(T)), 303 bitstr_unit(T)), 304 bitstr_type(T)), 305 bitstr_flags(T)); 306 letrec -> 307 fold(F, fold_pairs(F, S, letrec_defs(T)), letrec_body(T)); 308 module -> 309 fold_pairs(F, 310 fold_pairs(F, 311 fold_list(F, 312 fold(F, S, module_name(T)), 313 module_exports(T)), 314 module_attrs(T)), 315 module_defs(T)) 316 end. 317 318fold_list(F, S, [T | Ts]) -> 319 fold_list(F, fold(F, S, T), Ts); 320fold_list(_, S, []) -> 321 S. 322 323fold_pairs(F, S, [{T1, T2} | Ps]) -> 324 fold_pairs(F, fold(F, fold(F, S, T1), T2), Ps); 325fold_pairs(_, S, []) -> 326 S. 327 328 329%% @spec mapfold(Function, Initial::term(), Tree::cerl()) -> 330%% {cerl(), term()} 331%% 332%% Function = (cerl(), term()) -> {cerl(), term()} 333%% 334%% @doc Does a combined map/fold operation on the nodes of the 335%% tree. This is similar to <code>map/2</code>, but also propagates a 336%% value from each application of <code>Function</code> to the next, 337%% starting with the given value <code>Initial</code>, while doing a 338%% post-order traversal of the tree, much like <code>fold/3</code>. 339%% 340%% This is the same as mapfold/4, with an identity function as the 341%% pre-operation. 342%% 343%% @see map/2 344%% @see fold/3 345%% @see mapfold/4 346 347-spec mapfold(fun((cerl:cerl(), term()) -> {cerl:cerl(), term()}), 348 term(), cerl:cerl()) -> {cerl:cerl(), term()}. 349 350mapfold(F, S0, T) -> 351 mapfold(fun(T0, A) -> {T0, A} end, F, S0, T). 352 353 354%% @spec mapfold(Pre, Post, Initial::term(), Tree::cerl()) -> {cerl(), term()} 355%% Pre = (cerl(), term()) -> {cerl(), term()} 356%% Post = (cerl(), term()) -> {cerl(), term()} 357%% 358%% @doc Does a combined map/fold operation on the nodes of the 359%% tree. It begins by calling <code>Pre</code> on the tree, using the 360%% <code>Initial</code> value. It then deconstructs the top node of 361%% the returned tree and recurses on the children, using the returned 362%% value as the new initial and carrying the returned values from one 363%% call to the next. Finally it reassembles the top node from the 364%% children, calls <code>Post</code> on it and returns the result. 365 366-spec mapfold(fun((cerl:cerl(), term()) -> {cerl:cerl(), term()}), 367 fun((cerl:cerl(), term()) -> {cerl:cerl(), term()}), 368 term(), cerl:cerl()) -> {cerl:cerl(), term()}. 369 370mapfold(Pre, Post, S00, T0) -> 371 {T, S0} = Pre(T0, S00), 372 case type(T) of 373 literal -> 374 case concrete(T) of 375 [_ | _] -> 376 {T1, S1} = mapfold(Pre, Post, S0, cons_hd(T)), 377 {T2, S2} = mapfold(Pre, Post, S1, cons_tl(T)), 378 Post(update_c_cons(T, T1, T2), S2); 379 V when tuple_size(V) > 0 -> 380 {Ts, S1} = mapfold_list(Pre, Post, S0, tuple_es(T)), 381 Post(update_c_tuple(T, Ts), S1); 382 _ -> 383 Post(T, S0) 384 end; 385 var -> 386 Post(T, S0); 387 values -> 388 {Ts, S1} = mapfold_list(Pre, Post, S0, values_es(T)), 389 Post(update_c_values(T, Ts), S1); 390 cons -> 391 {T1, S1} = mapfold(Pre, Post, S0, cons_hd(T)), 392 {T2, S2} = mapfold(Pre, Post, S1, cons_tl(T)), 393 Post(update_c_cons_skel(T, T1, T2), S2); 394 tuple -> 395 {Ts, S1} = mapfold_list(Pre, Post, S0, tuple_es(T)), 396 Post(update_c_tuple_skel(T, Ts), S1); 397 map -> 398 {M , S1} = mapfold(Pre, Post, S0, map_arg(T)), 399 {Ts, S2} = mapfold_list(Pre, Post, S1, map_es(T)), 400 Post(update_c_map(T, M, Ts), S2); 401 map_pair -> 402 {Op, S1} = mapfold(Pre, Post, S0, map_pair_op(T)), 403 {Key, S2} = mapfold(Pre, Post, S1, map_pair_key(T)), 404 {Val, S3} = mapfold(Pre, Post, S2, map_pair_val(T)), 405 Post(update_c_map_pair(T,Op,Key,Val), S3); 406 'let' -> 407 {Vs, S1} = mapfold_list(Pre, Post, S0, let_vars(T)), 408 {A, S2} = mapfold(Pre, Post, S1, let_arg(T)), 409 {B, S3} = mapfold(Pre, Post, S2, let_body(T)), 410 Post(update_c_let(T, Vs, A, B), S3); 411 seq -> 412 {A, S1} = mapfold(Pre, Post, S0, seq_arg(T)), 413 {B, S2} = mapfold(Pre, Post, S1, seq_body(T)), 414 Post(update_c_seq(T, A, B), S2); 415 apply -> 416 {E, S1} = mapfold(Pre, Post, S0, apply_op(T)), 417 {As, S2} = mapfold_list(Pre, Post, S1, apply_args(T)), 418 Post(update_c_apply(T, E, As), S2); 419 call -> 420 {M, S1} = mapfold(Pre, Post, S0, call_module(T)), 421 {N, S2} = mapfold(Pre, Post, S1, call_name(T)), 422 {As, S3} = mapfold_list(Pre, Post, S2, call_args(T)), 423 Post(update_c_call(T, M, N, As), S3); 424 primop -> 425 {N, S1} = mapfold(Pre, Post, S0, primop_name(T)), 426 {As, S2} = mapfold_list(Pre, Post, S1, primop_args(T)), 427 Post(update_c_primop(T, N, As), S2); 428 'case' -> 429 {A, S1} = mapfold(Pre, Post, S0, case_arg(T)), 430 {Cs, S2} = mapfold_list(Pre, Post, S1, case_clauses(T)), 431 Post(update_c_case(T, A, Cs), S2); 432 clause -> 433 {Ps, S1} = mapfold_list(Pre, Post, S0, clause_pats(T)), 434 {G, S2} = mapfold(Pre, Post, S1, clause_guard(T)), 435 {B, S3} = mapfold(Pre, Post, S2, clause_body(T)), 436 Post(update_c_clause(T, Ps, G, B), S3); 437 alias -> 438 {V, S1} = mapfold(Pre, Post, S0, alias_var(T)), 439 {P, S2} = mapfold(Pre, Post, S1, alias_pat(T)), 440 Post(update_c_alias(T, V, P), S2); 441 'fun' -> 442 {Vs, S1} = mapfold_list(Pre, Post, S0, fun_vars(T)), 443 {B, S2} = mapfold(Pre, Post, S1, fun_body(T)), 444 Post(update_c_fun(T, Vs, B), S2); 445 'receive' -> 446 {Cs, S1} = mapfold_list(Pre, Post, S0, receive_clauses(T)), 447 {E, S2} = mapfold(Pre, Post, S1, receive_timeout(T)), 448 {A, S3} = mapfold(Pre, Post, S2, receive_action(T)), 449 Post(update_c_receive(T, Cs, E, A), S3); 450 'try' -> 451 {E, S1} = mapfold(Pre, Post, S0, try_arg(T)), 452 {Vs, S2} = mapfold_list(Pre, Post, S1, try_vars(T)), 453 {B, S3} = mapfold(Pre, Post, S2, try_body(T)), 454 {Evs, S4} = mapfold_list(Pre, Post, S3, try_evars(T)), 455 {H, S5} = mapfold(Pre, Post, S4, try_handler(T)), 456 Post(update_c_try(T, E, Vs, B, Evs, H), S5); 457 'catch' -> 458 {B, S1} = mapfold(Pre, Post, S0, catch_body(T)), 459 Post(update_c_catch(T, B), S1); 460 binary -> 461 {Ds, S1} = mapfold_list(Pre, Post, S0, binary_segments(T)), 462 Post(update_c_binary(T, Ds), S1); 463 bitstr -> 464 {Val, S1} = mapfold(Pre, Post, S0, bitstr_val(T)), 465 {Size, S2} = mapfold(Pre, Post, S1, bitstr_size(T)), 466 {Unit, S3} = mapfold(Pre, Post, S2, bitstr_unit(T)), 467 {Type, S4} = mapfold(Pre, Post, S3, bitstr_type(T)), 468 {Flags, S5} = mapfold(Pre, Post, S4, bitstr_flags(T)), 469 Post(update_c_bitstr(T, Val, Size, Unit, Type, Flags), S5); 470 letrec -> 471 {Ds, S1} = mapfold_pairs(Pre, Post, S0, letrec_defs(T)), 472 {B, S2} = mapfold(Pre, Post, S1, letrec_body(T)), 473 Post(update_c_letrec(T, Ds, B), S2); 474 module -> 475 {N, S1} = mapfold(Pre, Post, S0, module_name(T)), 476 {Es, S2} = mapfold_list(Pre, Post, S1, module_exports(T)), 477 {As, S3} = mapfold_pairs(Pre, Post, S2, module_attrs(T)), 478 {Ds, S4} = mapfold_pairs(Pre, Post, S3, module_defs(T)), 479 Post(update_c_module(T, N, Es, As, Ds), S4) 480 end. 481 482mapfold_list(Pre, Post, S0, [T | Ts]) -> 483 {T1, S1} = mapfold(Pre, Post, S0, T), 484 {Ts1, S2} = mapfold_list(Pre, Post, S1, Ts), 485 {[T1 | Ts1], S2}; 486mapfold_list(_, _, S, []) -> 487 {[], S}. 488 489mapfold_pairs(Pre, Post, S0, [{T1, T2} | Ps]) -> 490 {T3, S1} = mapfold(Pre, Post, S0, T1), 491 {T4, S2} = mapfold(Pre, Post, S1, T2), 492 {Ps1, S3} = mapfold_pairs(Pre, Post, S2, Ps), 493 {[{T3, T4} | Ps1], S3}; 494mapfold_pairs(_, _, S, []) -> 495 {[], S}. 496 497 498%% --------------------------------------------------------------------- 499 500%% @spec variables(Tree::cerl()) -> [var_name()] 501%% 502%% var_name() = integer() | atom() | {atom(), integer()} 503%% 504%% @doc Returns an ordered-set list of the names of all variables in 505%% the syntax tree. (This includes function name variables.) An 506%% exception is thrown if <code>Tree</code> does not represent a 507%% well-formed Core Erlang syntax tree. 508%% 509%% @see free_variables/1 510%% @see next_free_variable_name/1 511 512-spec variables(cerl:cerl()) -> [cerl:var_name()]. 513 514variables(T) -> 515 variables(T, false). 516 517 518%% @spec free_variables(Tree::cerl()) -> [var_name()] 519%% 520%% @doc Like <code>variables/1</code>, but only includes variables 521%% that are free in the tree. 522%% 523%% @see next_free_variable_name/1 524%% @see variables/1 525 526-spec free_variables(cerl:cerl()) -> [cerl:var_name()]. 527 528free_variables(T) -> 529 variables(T, true). 530 531 532%% This is not exported 533 534variables(T, S) -> 535 case type(T) of 536 literal -> 537 []; 538 var -> 539 [var_name(T)]; 540 values -> 541 vars_in_list(values_es(T), S); 542 cons -> 543 ordsets:union(variables(cons_hd(T), S), 544 variables(cons_tl(T), S)); 545 tuple -> 546 vars_in_list(tuple_es(T), S); 547 map -> 548 vars_in_list([map_arg(T)|map_es(T)], S); 549 map_pair -> 550 vars_in_list([map_pair_op(T),map_pair_key(T),map_pair_val(T)], S); 551 'let' -> 552 Vs = variables(let_body(T), S), 553 Vs1 = var_list_names(let_vars(T)), 554 Vs2 = case S of 555 true -> 556 ordsets:subtract(Vs, Vs1); 557 false -> 558 ordsets:union(Vs, Vs1) 559 end, 560 ordsets:union(variables(let_arg(T), S), Vs2); 561 seq -> 562 ordsets:union(variables(seq_arg(T), S), 563 variables(seq_body(T), S)); 564 apply -> 565 ordsets:union( 566 variables(apply_op(T), S), 567 vars_in_list(apply_args(T), S)); 568 call -> 569 ordsets:union(variables(call_module(T), S), 570 ordsets:union( 571 variables(call_name(T), S), 572 vars_in_list(call_args(T), S))); 573 primop -> 574 vars_in_list(primop_args(T), S); 575 'case' -> 576 ordsets:union(variables(case_arg(T), S), 577 vars_in_list(case_clauses(T), S)); 578 clause -> 579 Vs = ordsets:union(variables(clause_guard(T), S), 580 variables(clause_body(T), S)), 581 Vs1 = vars_in_list(clause_pats(T), S), 582 case S of 583 true -> 584 ordsets:subtract(Vs, Vs1); 585 false -> 586 ordsets:union(Vs, Vs1) 587 end; 588 alias -> 589 ordsets:add_element(var_name(alias_var(T)), 590 variables(alias_pat(T))); 591 'fun' -> 592 Vs = variables(fun_body(T), S), 593 Vs1 = var_list_names(fun_vars(T)), 594 case S of 595 true -> 596 ordsets:subtract(Vs, Vs1); 597 false -> 598 ordsets:union(Vs, Vs1) 599 end; 600 'receive' -> 601 ordsets:union( 602 vars_in_list(receive_clauses(T), S), 603 ordsets:union(variables(receive_timeout(T), S), 604 variables(receive_action(T), S))); 605 'try' -> 606 Vs = variables(try_body(T), S), 607 Vs1 = var_list_names(try_vars(T)), 608 Vs2 = case S of 609 true -> 610 ordsets:subtract(Vs, Vs1); 611 false -> 612 ordsets:union(Vs, Vs1) 613 end, 614 Vs3 = variables(try_handler(T), S), 615 Vs4 = var_list_names(try_evars(T)), 616 Vs5 = case S of 617 true -> 618 ordsets:subtract(Vs3, Vs4); 619 false -> 620 ordsets:union(Vs3, Vs4) 621 end, 622 ordsets:union(variables(try_arg(T), S), 623 ordsets:union(Vs2, Vs5)); 624 'catch' -> 625 variables(catch_body(T), S); 626 binary -> 627 vars_in_list(binary_segments(T), S); 628 bitstr -> 629 ordsets:union(variables(bitstr_val(T), S), 630 variables(bitstr_size(T), S)); 631 letrec -> 632 Vs = vars_in_defs(letrec_defs(T), S), 633 Vs1 = ordsets:union(variables(letrec_body(T), S), Vs), 634 Vs2 = var_list_names(letrec_vars(T)), 635 case S of 636 true -> 637 ordsets:subtract(Vs1, Vs2); 638 false -> 639 ordsets:union(Vs1, Vs2) 640 end; 641 module -> 642 Vs = vars_in_defs(module_defs(T), S), 643 Vs1 = ordsets:union(vars_in_list(module_exports(T), S), Vs), 644 Vs2 = var_list_names(module_vars(T)), 645 case S of 646 true -> 647 ordsets:subtract(Vs1, Vs2); 648 false -> 649 ordsets:union(Vs1, Vs2) 650 end 651 end. 652 653vars_in_list(Ts, S) -> 654 vars_in_list(Ts, S, []). 655 656vars_in_list([T | Ts], S, A) -> 657 vars_in_list(Ts, S, ordsets:union(variables(T, S), A)); 658vars_in_list([], _, A) -> 659 A. 660 661%% Note that this function only visits the right-hand side of function 662%% definitions. 663 664vars_in_defs(Ds, S) -> 665 vars_in_defs(Ds, S, []). 666 667vars_in_defs([{_, Post} | Ds], S, A) -> 668 vars_in_defs(Ds, S, ordsets:union(variables(Post, S), A)); 669vars_in_defs([], _, A) -> 670 A. 671 672%% This amounts to insertion sort. Since the lists are generally short, 673%% it is hardly worthwhile to use an asymptotically better sort. 674 675var_list_names(Vs) -> 676 var_list_names(Vs, []). 677 678var_list_names([V | Vs], A) -> 679 var_list_names(Vs, ordsets:add_element(var_name(V), A)); 680var_list_names([], A) -> 681 A. 682 683%% --------------------------------------------------------------------- 684 685%% @spec next_free_variable_name(Tree::cerl()) -> var_name() 686%% 687%% var_name() = integer() 688%% 689%% @doc Returns a integer variable name higher than any other integer 690%% variable name in the syntax tree. An exception is thrown if 691%% <code>Tree</code> does not represent a well-formed Core Erlang 692%% syntax tree. 693%% 694%% @see variables/1 695%% @see free_variables/1 696 697-spec next_free_variable_name(cerl:cerl()) -> integer(). 698 699next_free_variable_name(T) -> 700 1 + next_free(T, -1). 701 702next_free(T, Max) -> 703 case type(T) of 704 literal -> 705 Max; 706 var -> 707 case var_name(T) of 708 Int when is_integer(Int) -> 709 max(Int, Max); 710 _ -> 711 Max 712 end; 713 values -> 714 next_free_in_list(values_es(T), Max); 715 cons -> 716 next_free(cons_hd(T), next_free(cons_tl(T), Max)); 717 tuple -> 718 next_free_in_list(tuple_es(T), Max); 719 map -> 720 next_free_in_list([map_arg(T)|map_es(T)], Max); 721 map_pair -> 722 next_free_in_list([map_pair_op(T),map_pair_key(T), 723 map_pair_val(T)], Max); 724 'let' -> 725 Max1 = next_free(let_body(T), Max), 726 Max2 = next_free_in_list(let_vars(T), Max1), 727 next_free(let_arg(T), Max2); 728 seq -> 729 next_free(seq_arg(T), 730 next_free(seq_body(T), Max)); 731 apply -> 732 next_free(apply_op(T), 733 next_free_in_list(apply_args(T), Max)); 734 call -> 735 next_free(call_module(T), 736 next_free(call_name(T), 737 next_free_in_list( 738 call_args(T), Max))); 739 primop -> 740 next_free_in_list(primop_args(T), Max); 741 'case' -> 742 next_free(case_arg(T), 743 next_free_in_list(case_clauses(T), Max)); 744 clause -> 745 Max1 = next_free(clause_guard(T), 746 next_free(clause_body(T), Max)), 747 next_free_in_list(clause_pats(T), Max1); 748 alias -> 749 next_free(alias_var(T), 750 next_free(alias_pat(T), Max)); 751 'fun' -> 752 next_free(fun_body(T), 753 next_free_in_list(fun_vars(T), Max)); 754 'receive' -> 755 Max1 = next_free_in_list(receive_clauses(T), 756 next_free(receive_timeout(T), Max)), 757 next_free(receive_action(T), Max1); 758 'try' -> 759 Max1 = next_free(try_body(T), Max), 760 Max2 = next_free_in_list(try_vars(T), Max1), 761 Max3 = next_free(try_handler(T), Max2), 762 Max4 = next_free_in_list(try_evars(T), Max3), 763 next_free(try_arg(T), Max4); 764 'catch' -> 765 next_free(catch_body(T), Max); 766 binary -> 767 next_free_in_list(binary_segments(T), Max); 768 bitstr -> 769 next_free(bitstr_val(T), next_free(bitstr_size(T), Max)); 770 letrec -> 771 Max1 = next_free_in_defs(letrec_defs(T), Max), 772 Max2 = next_free(letrec_body(T), Max1), 773 next_free_in_list(letrec_vars(T), Max2); 774 module -> 775 next_free_in_defs(module_defs(T), Max) 776 end. 777 778next_free_in_list([H | T], Max) -> 779 next_free_in_list(T, next_free(H, Max)); 780next_free_in_list([], Max) -> 781 Max. 782 783next_free_in_defs([{_, Post} | Ds], Max) -> 784 next_free_in_defs(Ds, next_free(Post, Max)); 785next_free_in_defs([], Max) -> 786 Max. 787 788%% --------------------------------------------------------------------- 789 790%% label(Tree::cerl()) -> {cerl(), integer()} 791%% 792%% @equiv label(Tree, 0) 793 794-spec label(cerl:cerl()) -> {cerl:cerl(), integer()}. 795 796label(T) -> 797 label(T, 0). 798 799%% @spec label(Tree::cerl(), N::integer()) -> {cerl(), integer()} 800%% 801%% @doc Labels each expression in the tree. A term <code>{label, 802%% L}</code> is prefixed to the annotation list of each expression node, 803%% where L is a unique number for every node, except for variables (and 804%% function name variables) which get the same label if they represent 805%% the same variable. Constant literal nodes are not labeled. 806%% 807%% <p>The returned value is a tuple <code>{NewTree, Max}</code>, where 808%% <code>NewTree</code> is the labeled tree and <code>Max</code> is 1 809%% plus the largest label value used. All previous annotation terms on 810%% the form <code>{label, X}</code> are deleted.</p> 811%% 812%% <p>The values of L used in the tree is a dense range from 813%% <code>N</code> to <code>Max - 1</code>, where <code>N =< Max 814%% =< N + size(Tree)</code>. Note that it is possible that no 815%% labels are used at all, i.e., <code>N = Max</code>.</p> 816%% 817%% <p>Note: All instances of free variables will be given distinct 818%% labels.</p> 819%% 820%% @see label/1 821%% @see size/1 822 823-spec label(cerl:cerl(), integer()) -> {cerl:cerl(), integer()}. 824 825label(T, N) -> 826 label(T, N, dict:new()). 827 828label(T, N, Env) -> 829 case type(T) of 830 literal -> 831 %% Constant literals are not labeled. 832 {T, N}; 833 var -> 834 {As, N1} = 835 case dict:find(var_name(T), Env) of 836 {ok, L} -> 837 {A, _} = label_ann(T, L), 838 {A, N}; 839 error -> 840 label_ann(T, N) 841 end, 842 {set_ann(T, As), N1}; 843 values -> 844 {Ts, N1} = label_list(values_es(T), N, Env), 845 {As, N2} = label_ann(T, N1), 846 {ann_c_values(As, Ts), N2}; 847 cons -> 848 {T1, N1} = label(cons_hd(T), N, Env), 849 {T2, N2} = label(cons_tl(T), N1, Env), 850 {As, N3} = label_ann(T, N2), 851 {ann_c_cons_skel(As, T1, T2), N3}; 852 tuple -> 853 {Ts, N1} = label_list(tuple_es(T), N, Env), 854 {As, N2} = label_ann(T, N1), 855 {ann_c_tuple_skel(As, Ts), N2}; 856 map -> 857 case is_c_map_pattern(T) of 858 false -> 859 {M, N1} = label(map_arg(T), N, Env), 860 {Ts, N2} = label_list(map_es(T), N1, Env), 861 {As, N3} = label_ann(T, N2), 862 {ann_c_map(As, M, Ts), N3}; 863 true -> 864 {Ts, N1} = label_list(map_es(T), N, Env), 865 {As, N2} = label_ann(T, N1), 866 {ann_c_map_pattern(As, Ts), N2} 867 end; 868 map_pair -> 869 {Op, N1} = label(map_pair_op(T), N, Env), 870 {Key, N2} = label(map_pair_key(T), N1, Env), 871 {Val, N3} = label(map_pair_val(T), N2, Env), 872 {As, N4} = label_ann(T, N3), 873 {ann_c_map_pair(As,Op,Key,Val), N4}; 874 'let' -> 875 {A, N1} = label(let_arg(T), N, Env), 876 {Vs, N2, Env1} = label_vars(let_vars(T), N1, Env), 877 {B, N3} = label(let_body(T), N2, Env1), 878 {As, N4} = label_ann(T, N3), 879 {ann_c_let(As, Vs, A, B), N4}; 880 seq -> 881 {A, N1} = label(seq_arg(T), N, Env), 882 {B, N2} = label(seq_body(T), N1, Env), 883 {As, N3} = label_ann(T, N2), 884 {ann_c_seq(As, A, B), N3}; 885 apply -> 886 {E, N1} = label(apply_op(T), N, Env), 887 {Es, N2} = label_list(apply_args(T), N1, Env), 888 {As, N3} = label_ann(T, N2), 889 {ann_c_apply(As, E, Es), N3}; 890 call -> 891 {M, N1} = label(call_module(T), N, Env), 892 {F, N2} = label(call_name(T), N1, Env), 893 {Es, N3} = label_list(call_args(T), N2, Env), 894 {As, N4} = label_ann(T, N3), 895 {ann_c_call(As, M, F, Es), N4}; 896 primop -> 897 {F, N1} = label(primop_name(T), N, Env), 898 {Es, N2} = label_list(primop_args(T), N1, Env), 899 {As, N3} = label_ann(T, N2), 900 {ann_c_primop(As, F, Es), N3}; 901 'case' -> 902 {A, N1} = label(case_arg(T), N, Env), 903 {Cs, N2} = label_list(case_clauses(T), N1, Env), 904 {As, N3} = label_ann(T, N2), 905 {ann_c_case(As, A, Cs), N3}; 906 clause -> 907 {_, N1, Env1} = label_vars(clause_vars(T), N, Env), 908 {Ps, N2} = label_list(clause_pats(T), N1, Env1), 909 {G, N3} = label(clause_guard(T), N2, Env1), 910 {B, N4} = label(clause_body(T), N3, Env1), 911 {As, N5} = label_ann(T, N4), 912 {ann_c_clause(As, Ps, G, B), N5}; 913 alias -> 914 {V, N1} = label(alias_var(T), N, Env), 915 {P, N2} = label(alias_pat(T), N1, Env), 916 {As, N3} = label_ann(T, N2), 917 {ann_c_alias(As, V, P), N3}; 918 'fun' -> 919 {Vs, N1, Env1} = label_vars(fun_vars(T), N, Env), 920 {B, N2} = label(fun_body(T), N1, Env1), 921 {As, N3} = label_ann(T, N2), 922 {ann_c_fun(As, Vs, B), N3}; 923 'receive' -> 924 {Cs, N1} = label_list(receive_clauses(T), N, Env), 925 {E, N2} = label(receive_timeout(T), N1, Env), 926 {A, N3} = label(receive_action(T), N2, Env), 927 {As, N4} = label_ann(T, N3), 928 {ann_c_receive(As, Cs, E, A), N4}; 929 'try' -> 930 {E, N1} = label(try_arg(T), N, Env), 931 {Vs, N2, Env1} = label_vars(try_vars(T), N1, Env), 932 {B, N3} = label(try_body(T), N2, Env1), 933 {Evs, N4, Env2} = label_vars(try_evars(T), N3, Env), 934 {H, N5} = label(try_handler(T), N4, Env2), 935 {As, N6} = label_ann(T, N5), 936 {ann_c_try(As, E, Vs, B, Evs, H), N6}; 937 'catch' -> 938 {B, N1} = label(catch_body(T), N, Env), 939 {As, N2} = label_ann(T, N1), 940 {ann_c_catch(As, B), N2}; 941 binary -> 942 {Ds, N1} = label_list(binary_segments(T), N, Env), 943 {As, N2} = label_ann(T, N1), 944 {ann_c_binary(As, Ds), N2}; 945 bitstr -> 946 {Val, N1} = label(bitstr_val(T), N, Env), 947 {Size, N2} = label(bitstr_size(T), N1, Env), 948 {Unit, N3} = label(bitstr_unit(T), N2, Env), 949 {Type, N4} = label(bitstr_type(T), N3, Env), 950 {Flags, N5} = label(bitstr_flags(T), N4, Env), 951 {As, N6} = label_ann(T, N5), 952 {ann_c_bitstr(As, Val, Size, Unit, Type, Flags), N6}; 953 letrec -> 954 {_, N1, Env1} = label_vars(letrec_vars(T), N, Env), 955 {Ds, N2} = label_defs(letrec_defs(T), N1, Env1), 956 {B, N3} = label(letrec_body(T), N2, Env1), 957 {As, N4} = label_ann(T, N3), 958 {ann_c_letrec(As, Ds, B), N4}; 959 module -> 960 %% The module name is not labeled. 961 {_, N1, Env1} = label_vars(module_vars(T), N, Env), 962 {Ts, N2} = label_defs(module_attrs(T), N1, Env1), 963 {Ds, N3} = label_defs(module_defs(T), N2, Env1), 964 {Es, N4} = label_list(module_exports(T), N3, Env1), 965 {As, N5} = label_ann(T, N4), 966 {ann_c_module(As, module_name(T), Es, Ts, Ds), N5} 967 end. 968 969label_list([T | Ts], N, Env) -> 970 {T1, N1} = label(T, N, Env), 971 {Ts1, N2} = label_list(Ts, N1, Env), 972 {[T1 | Ts1], N2}; 973label_list([], N, _Env) -> 974 {[], N}. 975 976label_vars([T | Ts], N, Env) -> 977 Env1 = dict:store(var_name(T), N, Env), 978 {As, N1} = label_ann(T, N), 979 T1 = set_ann(T, As), 980 {Ts1, N2, Env2} = label_vars(Ts, N1, Env1), 981 {[T1 | Ts1], N2, Env2}; 982label_vars([], N, Env) -> 983 {[], N, Env}. 984 985label_defs([{F, T} | Ds], N, Env) -> 986 {F1, N1} = label(F, N, Env), 987 {T1, N2} = label(T, N1, Env), 988 {Ds1, N3} = label_defs(Ds, N2, Env), 989 {[{F1, T1} | Ds1], N3}; 990label_defs([], N, _Env) -> 991 {[], N}. 992 993label_ann(T, N) -> 994 {[{label, N} | filter_labels(get_ann(T))], N + 1}. 995 996filter_labels([{label, _} | As]) -> 997 filter_labels(As); 998filter_labels([A | As]) -> 999 [A | filter_labels(As)]; 1000filter_labels([]) -> 1001 []. 1002 1003-spec get_label(cerl:cerl()) -> 'top' | integer(). 1004 1005get_label(T) -> 1006 case get_ann(T) of 1007 [{label, L} | _] -> L; 1008 _ -> throw({missing_label, T}) 1009 end. 1010